Helmet retention system



FIG. 1 is a front perspective view of a nape for a helmet retention system in accordance with our new design;

FIG. 2 is a front elevational view of the nape shown in FIG. 1;

FIG. 3 is a rear elevational view of the nape shown in FIG. 1;

FIG. 4 is a right-side elevational view of the nape shown in FIG. 1;

FIG. 5 is a left-side elevational view of the nape shown in FIG. 1;

FIG. 6 is a top plan view of the nape shown in FIG. 1; and,

FIG. 7 is a bottom plan view of the nape shown in FIG. 1.

The broken lines shown in the drawings represent portions of the helmet retention system that form no part of the claimed design. 

CLAIM The ornamental design for a helmet retention system, as shown and described. 